The second Science 2024 article in the field of 3D printing technology was published on February 8th. A joint team from the University of Queensland, Australia (Jingqi Zhang et al.), Chongqing University (Ziyong Hou, Xiaoxu Huang), and the Technical University of Denmark has achieved in-situ alloying for the 3D printing process by adding Mo to Ti5553 metal powder.

Specifically, by precisely delivering molybdenum into the molten pool, molybdenum can act as a seed nucleus for crystal formation and refinement during each layer scan, facilitating the transition from large columnar crystals to a fine equiaxed and narrow columnar crystal structure. Molybdenum also stabilizes the desired β-phase and inhibits the formation of phase heterogeneity during thermal cycling, by which not only the strength of the 3D printed titanium alloys is improved, but also a perfect balance of ductility and tensile properties is achieved.

While TC4, the so-called workhorse of the titanium industry, has a recommended minimum elongation at break of 101 TP3T, the titanium 5553 prepared by this 3D printing has a great potential for application with a yield strength of 926 MPa and an elongation at break of 261 TP3T. The method is also expected to be applied to other metal powder mixtures and to customize different alloys with enhanced properties.